Oxygenate-to-olefin processes are well described in the art. Typically, oxygenate-to-olefin processes are used to produce predominantly ethylene and propylene. An example of such an oxygenate-to-olefin process is described in US Patent Application Publication No. 2011/112344, which is herein incorporated by reference. The publication describes a process for the preparation of an olefin product comprising ethylene and/or propylene, comprising a step of converting an oxygenate feedstock in an oxygenate-to-olefins conversion system, comprising a reaction zone in which an oxygenate feedstock is contacted with an oxygenate conversion catalyst under oxygenate conversion conditions, to obtain a conversion effluent comprising ethylene and/or propylene.
The publication further describes possible integration with a cracker. The publication also describes partially hydrogenating a C4 portion of the conversion effluent and/or cracker effluent and recycling at least part of the at least partially hydrogenated C4 as recycle feedstock to the cracker or oxygenate-to-olefins conversion system.
As market conditions change quite frequently, flexibility of a process system is important to its viability. This is especially important to a process that is integrated with other processes that provide feeds to the process or take outputs from the process. For example, in an oxygenate-to-olefin process, it is beneficial to be able to flexibly adjust the amount of each of the different products produced by the process. In addition, this process is typically integrated with other units so it is important to keep the feed supply constant even when product demand changes.